When you can't win a game...
In most games, with a reasonable amount of certainty (but not even 100%), you can say that all players are trying to win. In the case that a player isn't trying to win, players will have a secondary goal, but what that secondary goal is very uncertain and unless you know the player well, it cannot be predicted. Possibilities are:

* Trying to place as high as possible (2nd place >> 3rd place);
* Trying to attain highest possible score;
* Trying to maximize highest expected value of score;
* Trying to maximize difference between score and mean score;
* Trying to make the other players as close as possible;
* Trying to play as fast as possible;
* Trying to end the game as fast as possible;
* Trying to prolong the game as long as possible;
* Trying to make the rest of the game as simple as possible;
* Trying to make the rest of the game as chaotic as possible;
* Trying to make moves that are least likely to affect the current rankings;
* Trying to make moves that are most likely to affect the current rankings;
* Trying to make the winner be the player who has a worse winning record;
* Trying to make the most pleasing personal layout;
* Getting a specific cool-looking card in play;
* Getting "revenge" on the player that you think put you out of contention for winning;
* Trying to maximize the fun that other players are having;
* Trying to minimize the fun that other players are having;
* Trying to play as random as possible;
* Adopting a strategy from above, while making that fact dead obvious to all the other players;
* Adopting a strategy from above while hiding it from all the other players;
* Adopting a strategy from above while hiding it from all the other players, but surreptitiously dropping clues in some passive-aggressive manner that you might be playing that strategy.

I've seen all of these in games, in combination sometimes.